Photos and video posted on social media revealed extensive damage to floors and walls at the exchange, with debris strewn throughout the building. Dozens of people were reportedly evacuated.

Journalist Adam Harvey, the southeast Asia correspondent with the Australian Broadcasting Corporation, posted photos of people crowding around what appeared to be a large hole in the floor. He reported that a worker in the building had heard a loud “thud” before being evacuated.

The building is part of a two-tower complex that Islamist militants targeted with a suicide bombing in September 2000. However, police have ruled out a bomb as the cause of Monday’s collapse, Reuters reported.